In the not-so-distant past, the acceptable means to dispose of wastes were as water-borne wastes in sewage systems, as dry wastes or garbage for on-land dumping, and as a fuel (when significantly dry) in incinerators. Biological attack on water-borne wastes or on-land fill wastes would reduce the total waste content to an acceptable level for landfill and into natural waters for disposal. Even the ash from incineration was a suitable material for additional landfill.
The wastes of our modern society are a radical change from the past. Materials that compose our wastes are biorefractory, often toxic, and sometimes carcinogenic. On incineration, modern wastes may produce hazardous gases that evolve into our atmosphere and leave ash containing toxic heavy metals. A major problem arises because governmental agencies are unwilling to ask the public to support anything beyond the traditional means of waste handling. Efforts to improve traditional sewage treatment plants and efforts to confine all wastes to landfills by sealing against extraction of toxic matter are proving to be less than adequate.
There has not heretofore been provided a fully safe and effective means for treatment of waste materials, especially those found in domestic and industrial waste water.